Lead particle size and its association with firing conditions and range maintenance: implications for treatment

Six firing range soils were analyzed, representing different environments, firing conditions, and maintenance practices. The particle size distribution and lead (Pb) concentration in each soil fraction were determined for samples obtained from the backstop berms. The main factors that were found to influence Pb fragment size were the type of soil used to construct the berms and the type of weapon fired. The firing of high velocity weapons, i.e., rifles, onto highly angular soils induced significant fragmentation of the bullets and/or pulverization of the soil itself. This resulted in the accumulation of Pb in the finer soil fractions and the spread of Pb contamination beyond the vicinity of the backstop berm. Conversely, the use of clay as backstop and the use of low velocity pistols proved to be favorable for soil clean-up and range maintenance, since Pb was mainly present as large metallic fragments that can be recovered by a simple screening process. Other factors that played important roles in Pb particle size distribution were soil chemistry, firing distance, and maintenance practices, such as the use of water spray for dust suppression and deflectors prior to impact. Overall, coarse Pb particles provide much easier and more cost-effective maintenance, soil clean-up, and remediation via physical separation. Fine Pb particles release Pb more easily, pose an airborne Pb hazard, and require the application of stabilization/solidification treatment methods. Thus, to ensure sustainable firing range operations by means of cost-effective design, maintenance, and clean-up, especially when high velocity weapons are used, the above mentioned factors should be carefully considered.     

The impact on tropospheric ozone formation on the implementation of a program for mobile emissions control: a case study in São Paulo,Brazil

The main sources of reactive hydrocarbons (RHC) and nitrogen oxides (NO_x), ozone precursors, in the Metropolitan Area of São Paulo (MASP) in the southeast of Brazil are emissions from vehicles fleets. Ambient surface ozone and particulate matter concentrations are air quality problem in the MASP. This study examined the impact that implementing a control program for mobile emissions has on ozone concentrations, An episode of high surface ozone concentrations occurring in the MASP during the March 13–15, 2000 period was used as a case study that was modeled for photochemical oxidants using the California Institute of Technology/Carnegie Mellon University three-dimensional photochemical model. Different scenarios were analyzed in relationship to the implementation of the Programa Nacional de Controle de Poluição por Veículos Automotores (PROCONVE, National Program to Control Motor Vehicle Pollution). Scenario 1 assumed that all vehicles were operating within PROCONVE guidelines. Scenarios 2 and 3 considered hypothetical situations in which the PROCONVE was not implemented. Scenario 2 set the premise that vehicles were using pre-1989 technology, whereas scenario 3 allowed for technological advances. A base case scenario, in which the official emission inventory for the year 2000 was employed, was also analyzed. The CIT model results show agreement with most measurements collected during 13–15 March 2000 modeling episode. Mean normalized bias for ozone, CO, RHC and NO _x are approximately 9.0, 6.0, ?8.3, 13.0%, respectively. Tropospheric ozone concentrations predicted for scenario 2 were higher than those predicted for scenarios 1, 3 and base case. This study makes a significant contribution to the evaluation of air quality improvement and provides data for use in evaluating the economic costs of implementing a program of motor vehicle pollution control aimed at protecting human health.     

Mitigation of methane emission from an old unlined landfill in Klintholm,Denmark using a passive biocover system

Methane generated at landfills contributes to global warming and can be mitigated by biocover systems relying on microbial methane oxidation. As part of a closure plan for an old unlined landfill without any gas management measures, an innovative biocover system was established. The system was designed based on a conceptual model of the gas emission patterns established through an initial baseline study. The study included construction of gas collection trenches along the slopes of the landfill where the majority of the methane emissions occurred. Local compost materials were tested as to their usefulness as bioactive methane oxidizing material and a suitable compost mixture was selected. Whole site methane emission quantifications based on combined tracer release and downwind measurements in combination with several local experimental activities (gas composition within biocover layers, flux chamber based emission measurements and logging of compost temperatures) proved that the biocover system had an average mitigation efficiency of approximately 80%. The study showed that the system also had a high efficiency during winter periods with temperatures below freezing. An economic analysis indicated that the mitigation costs of the biocover system were competitive to other existing greenhouse gas mitigation options.     

Towards a framework for assessment and management of cumulative human impacts on marine food webs

Effective ecosystem‐based management requires understanding ecosystem responses to multiple human threats, rather than focusing on single threats. To understand ecosystem responses to anthropogenic threats holistically, it is necessary to know how threats affect different components within ecosystems and ultimately alter ecosystem functioning. We used a case study of a Mediterranean seagrass (Posidonia oceanica) food web and expert knowledge elicitation in an application of the initial steps of a framework for assessment of cumulative human impacts on food webs. We produced a conceptual seagrass food web model, determined the main trophic relationships, identified the main threats to the food web components, and assessed the components’ vulnerability to those threats. Some threats had high (e.g., coastal infrastructure) or low impacts (e.g., agricultural runoff) on all food web components, whereas others (e.g., introduced carnivores) had very different impacts on each component. Partitioning the ecosystem into its components enabled us to identify threats previously overlooked and to reevaluate the importance of threats commonly perceived as major. By incorporating this understanding of system vulnerability with data on changes in the state of each threat (e.g., decreasing domestic pollution and increasing fishing) into a food web model, managers may be better able to estimate and predict cumulative human impacts on ecosystems and to prioritize conservation actions.     

Challenges in modeling detailed and complex environmental data sets: a case study modeling the excess partial pressure of fluvial $$\hbox {CO}_2$$ CO 2

Environmental and Ecological Statistics - Advances in sensor technology enable environmental monitoring programmes to record and store measurements at a high temporal resolution, enhancing the...     

Influence of the composition of the initial mixtures on the chemical composition,physicochemical properties and humic-like substances content of composts

The influence of the proportion of C- and N-rich raw materials (initial C/N ratio) and bulking agent on the chemical functional groups composition, humic-like substances (HS-like) content and physicochemical properties of composts was assessed. To achieve these goals, seven initial mixtures (BA1–6 and C1) of dog food (N-rich raw material) were composted with wheat flour (C-rich raw material). Composts were analyzed in terms of chemical functional groups, physicochemical, maturity and stability parameters.The C-rich raw material favored the formation of oxidized organic matter (OM) during the composting process, as suggested by the variation of the ratios of the peaks intensity of FT-IR spectra, corresponding to a decrease of the polysaccharides and an increase of aromatic and carboxyl-containing compounds. However, although with high proportion of C-rich raw material, mixtures with low initial C/N seems to have favored the accumulation of partially oxidized OM, which may have contributed to high electrical conductivity values in the final composts. Therefore, although favoring the partial transformation of OM into stabilized HS-like, initial mixtures with high proportion of C-rich raw material but with low initial C/N led to unstable composts.On the other hand, as long as a high percentage of bulking agent was used to promote the structure of biomass and consequently improve of the aeration conditions, low initial C/N was not a limiting factor of OM oxidation into extractable stabilized humic-like acids.     

What is the acceptable margin of error for the oxygen uptake method in evaluating the reactivity of organic waste?

The acceptable margin of error for the organic waste reactivity measured by the oxygen uptake method was assessed. Oxygen uptake was determined by the Dynamic Respiration Index (DRI) (mgO₂/kgVS h). The composed uncertainty (uC) of the experimental set up used for the DRI test was evaluated and the uncertainty (u) of all the components of the apparatus was evaluated. A procedure for calculating the uC of the apparatus is proposed. The components affecting the uC of the DRI to a more significant extent were the one of the oxygen mass rate and the u of the amount of VS in the sample analyzed. For a confidence level of 99.73%, the extended uC (UC) interval for a DRI = 1024 mgO₂/kgVS h was ±440 mgO₂/kgVS h, whereas for a DRI = 3489 mgO₂/kgVS h, the UC interval was ±1288 mgO₂/kgVS h. When oxygen consumption and VS content become lower than 600 mgO₂/h and 0.9 kg, respectively, the UC interval is similar to the measured DRI.     

A knowledge network to promote the use and valorization of wild food plants in the Pantanal and Cerrado,Brazil

Regional Environmental Change - The conservation and use of wild food plants should include local people in the decision-making process, and many countries have done so. However, interacting with...